Gene Activity in Early Development

Gene Activity in Early Development reviews the state of knowledge regarding genomic function in the programming and operation of what Bonnet, in 1762, described as "the miracle of epigenesis." The book is divided into four sections. Section I is concerned with gene activity in early embryogenesis, with the time of onset and the nature of embryo genome control, and with recent attempts to analyze the shifting patterns of gene expression as development proceeds. Section II reviews various classic and recent studies relevant to the phenomenon of cytoplasmic localization of morphogenetic potential and discusses the significance, from a contemporary vantage point, of this often neglected area of developmental biology. Section III deals with genomic function in oogenesis, beginning with a general survey of what could be described loosely as the natural history of the oocyte nucleus, and proceeding to current attempts to understand the character and the ultimate function of the oocyte gene products. Section IV discusses various aspects of the general problem of gene regulation in animal cells.

Preface

I Gene Activity in Early Embryogenesis

1. The Variable Gene Activity Theory of Cell Differentiation

2. The Onset of Genome Control in Embryogenesis

3. Early Molecular Indices of Differentiation

4. RNA Synthesis in the Early Embryo

5. The Fate and Function of Early Informational RNA

6. Maternal Template RNA

Conclusions

II Cytoplasmic Localization and the Onset of Differentiation

1. The Localization Phenomenon

2. Localization and Preformationism

3. Definitive Experimental Evidence for Localization

4. Regulative and Mosaic Development, and the Universality of Morphogenetic Determinants in Egg Cytoplasm

5. Demonstrations of Localization in Regulative Embryos

6. Interpretations of the Localization Phenomenon

Conclusions

III Gene Function in Oogenesis

1. Origin and Differentiation of the Female Germ Line

2. Clues to Oocyte Genome Function from Organisms Displaying Chromosome Elimination

3. Accessory Cell Functions in Oogenesis

4. Gene Activity in the Oocyte Nucleus: Ribosomal RNA Synthesis

5. Gene Activity in the Oocyte Nucleus: Synthesis of Informational RNA

6. DNA of the Oocyte Cytoplasm

Conclusions

IV Immediacy of Gene Control and Theregulation of Gene Activity

1. Very Long-Lived Gene Products

2. Moderately Long-Lived Informational RNA

3. Rapidly Decaying Template RNA

4. The Rapidity of Variations in Gene Activity in Differentiated Cells

5. Characteristics of Bacterial Repression-Derepression Systems

6. Characteristics of Gene Regulation Systems in Differentiated Cells

7. Some Hypotheses Regarding the Nature of Genomic Regulation in Differentiated Cells

Conclusion

Bibliography

Index